I would argue the parenting is of much greater value than the birth itself. In general, the better the parenting, the greater the net value of the child to society.

> We conclude that the US government should be willing to pay up to $290,000, overall, to each parent who gives birth.

This is a weirdly short-sighted suggestion after all that analysis. Getting paid to have children can easily cause the value metric per child to plummet; not to mention the probable suffering caused to the children whose parents might try to abuse it.

If you want to increase births, things like subsidizing daycare and after-care and taking steps to ensure the quality of care are helpful. Making the cost of having children lower indirectly is much less likely to be abused.

Additionally, if you want to increase the value of children to society, making teaching a more appealing profession (i.e. paying more) and taking steps to ensure the quality of teachers are helpful.